Gaseous fuel mixture



per square inch; an .for us'e,

pounds.

mechanical difiieulties hydrogen blow-pipe,

drogen is phenomenally di Patented June 21, l93 2 UNITED- sTATEs PATENTOFFICE GEORGE C. QUELCH, OF OAKMON T, PENNSYLVANIA, ASSIGNOR, BY, MESNEASSIGN- MENTS, TO UNION CARBIDE AND CARBON RESEARCH LABORATORIES, INC.,0] NEW YORK, Y., A CORPORATION OF NEW YORK GASEOUS FUEL MIXTURE 11' 0Drawing.

transported in tanks under very high pres sure, say 120 atmos heres, or,1800 pounds the respective tanks are connected to-the torch throughseparate valves whereby each'gas is greatly expanded and its pressurereduced to that required for proper blow-pipe operation, say 5 Suchenormous expansion produces great refri crating effects, which are muchgreater for eavier gases than for lighter ones. These effects are notlikely to introduce any in-operation of the valves, where the fuel ispure dry hydrogen, used with pure dr oxygen, both of which are easilyattainab e by methods long practiced in connection with the well knownoxythereason being that and freezing points far below anything that canbe reached by expansion from even such great pressures as 120atmosfpheres, and hyerent from all other gases in that it actually heatsup instead of refrigerating when expanded through the above range,without doing work. For the latter reason there seems to be nodifiiculty 5 even when the hydrogen is diluted with small percentages ofother well known fuel (gases containing combustible carbon compoun s as,for instance, water gas, producer gas and illuminating gas.

As contrasted with the above, an important feature of my presentinvention is the production of a fuel gas mixture for the abovepurposes, which is mainly hydrocarbon and therefore of very greatcalorific or fuel value pfr cubic foot, 'as compared with hydrogen.

y hydrocarbon gases are so'selected and are used with such percentagesof hydrogen that no mechanical difficulties are introduced by freezingeffects when the gas is expanded for use in the torch. In my preferredfuel gas Application filed June a, 1926.. Serial No. 114,578.

mixture, the carbon constituent is mainly methane (CH diluted with aminor percentage of hy rogen, the higher hydrocarbons, ethane, propane(0 1-1 or the like being eliminated as far as ractical, usually lessthan 2% and prefera 1y substantially less than 1% being pesent inthemixture.

For certain critlcal values for the diluent, say 45% down to 38%hydrogen, I have found that when used in a blow torch with pure oxygenin the usual way, the flame produced by my fuel gas will cut metalplates faster than the best of the other fuel gas mixtures now on themarket. Moreover, the volume of pure oxygen that must be supplied to thetorch for a given volume of my gas for perfect combustion is less thansix-tenths that required for pure hydrogen, my surplus being availablefor burning the heated iron.

he appearance of the resulting magnetic oxide of iron indicates completecombustion of the metal and none of the oxide tends to cling to theedges of the iron being cut as is common to most fuel gases. Moreover,with my gas it has been found possible to get combast on of the ironwithout the use of the oxygim Jet, which indicates that even under or-'nary flameadjustment the gas striking the metal is highly oxidizing.

While my theories explaining the critical percentage desirable for thehydro n diluent have not been verified, I find t at good results areobtainable first, byrecognizing the general principle thatsubstantialpercentages of hydrogen 1n the hydrocarbon gases improve ignition andincrease the tems decreased from 48% down to 38 0, would indicate thatthere should be still further improvement below. 38%, but this is notthe case with such methane gases as I have been able to obtain. Mypresent theory is, thatthe desirable minimum percentage of hydrogendepends on the quantities and liquefying points of the small percentagesof ethane or other higher hydrocarbons that are contained in the primarygas, above described as being mainly methane. My gaseous mixtureconsisting mostly of methane and conta-inin 1% or less of ethanepreferably contains as di uent not less than 35% to 40% of hydrogen andslightly increasing percentages of ethane seem to requirecorrespondingly increased percentages of hydrogen. Proceeding on thisprinciple,

hydrogen diluent of the methane affords a reasonably practical care of aslight excess of ethane over 1%.- The higher percentages of hydrogenmake the oxygen consuming or fuel value ofthe mixture only 4 to 1 as 38mixture.

e; sures in an monly heavier gases,

The above interdependence of percentages seemsto'be the fuel gases arecustomarily tanks in which they'fare stored under say; 00 pounds or 120atmospheres per a When released from such presexpansion v. lve such asis comused for the purpose, results in. great latent heat absorptionand'the refrigerating effect is very great except in the case ofhydrogen. Consequently-with some of the that is hydrocarbon gases hawing boiling points hi her' than. methane, freezing and resultingirregularity of operation of the valves is likely to occur.

Hydrogen, however, diifers from all" other gasesin that insteadofcooling it actually heatsupwhen permitted to expand without doingwork, at least for all pressures below 3,000 pounds per square inch.Hence, for my pressures, the expanding hydrogen functions as a heaterandthere shou d beenough. ofit in the mixture to keep the refrigerating efects of the other gases within safe limits.

I find that so far as concerns the methane,

square inch.

. in practice the ranges and rates ofexpansion and the resulting i notbe altogether clear, any one faction of methane,

'it even solidified pressure of, say,1800 pounds to the workingtempcratures'are not sufficient to cause any'trouble by partialliquebecause its critical temperature is 117 below zero F. though itscritical pressure is only 825 pounds. p H On the other hand, ethane hasthevastly while critical pressure is approximately; 7 pounds. Inpractice, ethane can be liquefied and perhaps part of by sudden-dropfrom tank pressure of, say, 5 pounds. The same tendenc exists inhyrli'o'carbons of the same series.

P sibly also as'a help with respect to the'methane', the pure hydrogendiluent proves entirely effective if usedin the above describeercentages; While the reason for this may familiar with the use of purehydrogen in the oxyhydrogen torch will recognize the fact that there isno refrigerating effect on the'reducing valve,

I have found a.44% to 45% the heavy hydrocarbon gases such as a lesscontrast in against 5 to 1 for the i due to the fact that 1n comrnerci'al' practice,

transported in and used from enormous pressures,

cient hydrogen may ;which'is adapted to be expanded from highercriticaltemperature of 95 above zero gas tocondense while expanding init'ls probable that the the case of other of the higher Ascountenvailing this tendency of the ethane and even where the hydro en isexpanded in one stage from 1800 poun s ressure to 5 pounds, whereasthere is 'marke refrigeratin efiect on the reducing valve of the othertan from which the oxygen comes. In this connection, it may be notedthat the specific gravity of ox gen is 16 times that of the-hydrogenalsothere is a si ilarcontrast in the case oi ethane, as hydrogen, an thecase of methane which is only 8 times as heavy as hydrogen.

The principle of partial pressures also figures in this connection.

For instance, suppose a typical gaseous mixture in accord comprisingmethane ethane- 1% and hydrogen 39%. The law of partial pressuresindicates that so far-as concerns liquefying, the effective pressure onthe methane must reckoned as 60% of the 1080, whilethe pressure on the1% of ethane will be 1% or'less of the 1800, that is, 18 pounds, w hichis a negli ible ressure so far as concerns liquefying. here ore,thedanger to the ethane, is from the refrigerating eifect of the 60%methane when expanded from its effective partial pressure of v1080pounds per square inch. At this point, it is logical, as wellas simpleand safe, to shift from theory to practice andvstate my discovery that38% 'to-.{i0% or. pure hydrogen will prevent 1% of ethane. fromliquefyin notwithstanding the refrigerating effect 0 thane.

The hydrocarbon content and a portion of the hydrogen content of'a gasof the above composition may be procured fromnatural gas by knowncracking and separation processes and thereby obtain a dr gaseousmixture containing about 5% by rogen, 1% ethane and, 94%.methane'1wi'thsmal percentages of higher hydrocarbons. To this mixture su be added toproduce a osition described herein 1800 lbs..pressure per sq. inch to 5lbs. pressure per sq. inch withoutcausing particles of the one stagefrom the upper to lower pressure. 'The irregular and defective operationof the ressure'regulator and reducing valve which ave been heretoforecaused by liquid and frozen particles passing through and adhering tothe pressure regulating and reducing valve is thus avoided gas 1 Whenused for cutting iron, the fuel perfect combustion will be used for thepre-' which is'15 times as heavy gas of the com with the amount ofoxygen necessary heating of the metal. This flame is projected orimpinged upon temperature of the iron to r be cut and the the metal isthereby raise to a point where the metal is rapidly oxidized, that is,burns when a'jet of oxygen under pressure is pro ected against 1t.

The metallic ance with my invention,

the 60% of me oxide is carried awa or to the bottom force of t againstthe heated metal. e consumption of oxygen therefore will depend, firstupon the above d tity required for complete combustion of the uel gas tocause preheating, plus the quantity of oxygen required for the completeoxidation of the metal being cut, this latterbeing directy proportionalto the weight of metal oxidized, theoretically ,--on e cubic foot ofoxygen or .22 pounds'of iron.

It naturally follows that the true basis of comparison of my fuel eprior art is quantities requlred to be used oxygen for preheating.

y rogen may be selected for comparison with my gas, because they seem torepresent the two extremes. In general cutting prac tice it is customaryto estimate thatequal hydrogen will require one cylinder of oxygen. Ofthis volume approximately cubic feet of oxygen with 200 cubic feetof'hydrogen will be used for preheating, the balance of 100 cubic feet 0ogygen being used for the actual oxidation of the metal In comparisonwith the above, 100 quires only 27.5

eating.

operation.

In this connection, it

certain other fuel gas mixtures now on the market seem to retard theactual cutting operation, the iron oxide slag clinging to the underedges of the tracting from th form a given length of cut.

ith my fuel gases, the appearance of the magnetic oxide of combustion ofthe metal and none of tends to cli cut described, and th' with theminimum the cuttin jet. been foun 0d of prod ugingaaehighly comnnxtureconsisting o'ffhydrogen, methane and a small percentage of at gases withthose of densation of any of th is to be noted that mainly of methaneand conexcess of ab mixing said last named mixture with gen until theresulting posed of pounds per square same, a mixture drogen 38% to 45%,eth methane the Signed at Verona, in the county of Allegheny, and Stateof Pen ylvam'a, this fifth ay of June, A. D. 1926.

from about 1800 pounds per

